1. No. 2 The Introduction of Arthrology of Arthrology

2. Chapter 2 Arthrology

3. Section 1 Introduction  The bones are connected together by fibrous, cartilaginous or osseous tissues at different parts of their surfaces, and such a connection is designated by the name of joint or articulation.  According to the movement they are classified into two types of joints, i.e. synarthroses (syn=together; arthron=joint) and diarthroses.

4. Ⅰ. Synarthroses The synarthroses (immovable articulations) include the fibrous joints, the cartilaginous joints and synostoses. However, slight movement is, in fact, permitted in some synarthroses. The synarthroses (immovable articulations) include the fibrous joints, the cartilaginous joints and synostoses. However, slight movement is, in fact, permitted in some synarthroses.

5. Ⅰ ) The Fibrous Joints The fibrous joints include all the articulations in which the bones are held tightly together by fibrous connective tissue. The bones are united by fibrous tissue without any cavity. There are two types of fibrous joints, sutures and syndesmoses, depending in part on the length of the connective tissue fibers that hold the bones together. The fibrous joints include all the articulations in which the bones are held tightly together by fibrous connective tissue. The bones are united by fibrous tissue without any cavity. There are two types of fibrous joints, sutures and syndesmoses, depending in part on the length of the connective tissue fibers that hold the bones together.

6. 1. Sutures 1. Sutures The separated bones are held together by a thin layer of fibrous tissue. The union is extremely tight and there is little or no movement between the bones. This kind of joint is found only between the flat bones of the skull and can be fused by ossification from the early 20s and progresses throughout the life. The separated bones are held together by a thin layer of fibrous tissue. The union is extremely tight and there is little or no movement between the bones. This kind of joint is found only between the flat bones of the skull and can be fused by ossification from the early 20s and progresses throughout the life.

8. 2. Syndesmoses 2. Syndesmoses The bones are united by a ligament or a sheet of fibrous tissue, e.g., the yellow ligaments join the adjacent two vertebral arches, and the interoseous membrane joins the radius with the ulna. The bones are united by a ligament or a sheet of fibrous tissue, e.g., the yellow ligaments join the adjacent two vertebral arches, and the interoseous membrane joins the radius with the ulna. Bones joined by syndesmoses are not held as firmly as those joined by sutures. Syndesmoses can permit some movement. Bones joined by syndesmoses are not held as firmly as those joined by sutures. Syndesmoses can permit some movement.

10. Ⅱ ) Cartilaginous Joints The bones are united by cartilage. They allow little or no movement. The bones are united by cartilage. They allow little or no movement. There are two types of cartilaginous joints: There are two types of cartilaginous joints: synchondroses synchondroses symphyses. symphyses.

11. 1. Synchondroses 1. Synchondroses The bones of a synchondrosis joint are jointed by hyaline cartilage.For example, the epiphysial cartilage plate connects the ends and the shaft of a long bone. The bones of a synchondrosis joint are jointed by hyaline cartilage.For example, the epiphysial cartilage plate connects the ends and the shaft of a long bone. Many synchondroses are temporary joints, with the cartilage eventually being replaced by bone. This replacement occurs between the epiphyses and the diaphysis of long bones (where the epiphyseal cartilages are replaced) and between certain skull bones. The joints formed between the first ten ribs and their costal cartilages are permanent synchondroses. Many synchondroses are temporary joints, with the cartilage eventually being replaced by bone. This replacement occurs between the epiphyses and the diaphysis of long bones (where the epiphyseal cartilages are replaced) and between certain skull bones. The joints formed between the first ten ribs and their costal cartilages are permanent synchondroses.

13. 2. Symphyses 2. Symphyses The connecting material is a broad, flat disc of fibrocartilage. The connecting material is a broad, flat disc of fibrocartilage. This kind of joint is found between the bodies of vertebrae. The pubic symphysis is another example of these joints. The symphysis does not ossify throughout the life. This kind of joint is found between the bodies of vertebrae. The pubic symphysis is another example of these joints. The symphysis does not ossify throughout the life.

16. Ⅲ ) Synostoses The bones are united by the ossification of the fibrous joint or synchondrosis between them, e.g., the synostoses between the ilium, ischium and pubis of the hip bone. The bones are united by the ossification of the fibrous joint or synchondrosis between them, e.g., the synostoses between the ilium, ischium and pubis of the hip bone.

17. Ⅱ. Diarthroses The Diarthroses (movable articulations, synovial joints) there is a space between the articulating bones, called the synovial cavity. This kind of joints normally provide free movement. The Diarthroses (movable articulations, synovial joints) there is a space between the articulating bones, called the synovial cavity. This kind of joints normally provide free movement. The bones are connected by the joint capsule and ligament. There is a space between the articulating bones, called the synovial cavity. This kind of joints normally provide free movement. We called them as Synovial Joints The bones are connected by the joint capsule and ligament. There is a space between the articulating bones, called the synovial cavity. This kind of joints normally provide free movement. We called them as Synovial Joints

18. Ⅰ ) The Essential Structures of a Synovial Joint The essential structures are as follows: The essential structures are as follows: Articular surface, Articular surface, Articular capsule, Articular capsule, Articular cavity. Articular cavity.

21. 1. The articular surfaces 1. The articular surfaces They are usually covered by the articular cartilage. The articular cartilage is a thin layer of hyaline cartilage that covers the smooth articular surfaces of the bones. It is very smooth but uneven in the thickness. They are usually covered by the articular cartilage. The articular cartilage is a thin layer of hyaline cartilage that covers the smooth articular surfaces of the bones. It is very smooth but uneven in the thickness.

22. 2. The articular (joint) capsule 2. The articular (joint) capsule  The articular capsule is a double-layered membrane that surrounds and encloses the joint. It is attached to the periphery of the articular surface and adjacent bone surface.  The outer layer of the capsule (fibrous membrane) is formed by dense connective tissue whose fibers are firmly joined to the periosteum of the bones and is riched in blood vessels and nerves. Its thickness is corresponding to the functions of the joint.

23.  The inner layer of the articular capsule is referred to as the synovial membrane. It consists of lose connective tissue whose inner surface is well supplied with capillaries. The membrane, which is often thrown into folds that project into the joint cavity, invests the inside of the fibrous membrane, except for the surface of the articular cartilages. It is very thin, glistening and slippery.

24. The synovial membrane secretes a thick fluid called synovial fluid (synovia). Synovial fluid provides nourishment to the articular cartilages, and lubricates the joint surfaces. The synovial membrane secretes a thick fluid called synovial fluid (synovia). Synovial fluid provides nourishment to the articular cartilages, and lubricates the joint surfaces. 3. The articular (joint) cavity It is a closed cavity formed by the synovial membrane and the articular cartilage. It contains a proper amount of synovia. Its pressure is negative to the atmosphere pressure. It is a closed cavity formed by the synovial membrane and the articular cartilage. It contains a proper amount of synovia. Its pressure is negative to the atmosphere pressure.

25. Ⅱ ) The Accessory Structures of Synovial Joints The accessory structures are as follows: The accessory structures are as follows: The ligaments The ligaments The articular disc (or cartilage) The articular disc (or cartilage) The articular labrum (lip) The articular labrum (lip)

26. 1. The ligaments The joints are usually strengthened by accessory ligaments which are either inside or outside the joint (the intracapsular and extracapsular ligament). These ligaments are designed to limit movements of the joint in undesirable direction. The joints are usually strengthened by accessory ligaments which are either inside or outside the joint (the intracapsular and extracapsular ligament). These ligaments are designed to limit movements of the joint in undesirable direction.

27. 2. The articular disc (or cartilage) It is usually a fibrocartilage and divides the joint cavity partially or completely into two parts. It is usually a fibrocartilage and divides the joint cavity partially or completely into two parts. Functions: It makes the articular surfaces more fitting with each other and diminishes the shock of the joint. Functions: It makes the articular surfaces more fitting with each other and diminishes the shock of the joint. 3. The articular labrum (lip) It is a pliable, fibrocartilaginous ring that helps to deepen the articular surface for the bones, e.g., the labrum of the glenoid cavity of the scapula. It is a pliable, fibrocartilaginous ring that helps to deepen the articular surface for the bones, e.g., the labrum of the glenoid cavity of the scapula.

30. Ⅲ ) The Movement of Joint The basic movements of joints are as follows: 1. Flexion and extension 2. Adduction and abduction 3. Rotation 4. Circumduction

31. 1. Flexion and extension These two antagonistic movements are performed in the coronal axis. The flexion decreases the angle between the adjoining bones, whereas the extension increases the angle. 2. Adduction and abduction The movements are perfomed in the sagittal axis. The adduction means the movement of a bone toward the midline of the body. The abduction means the movement of a part away from the midline of the body.

32. 3. Rotation It means moving a bone around its vertical axis. It includes medial rotation and lateral rotation. Pronation and supination: The movements are specially for the forearm. The pronation is a movement of the forearm in which the palm of the hand is turned backward. The supination is the movement in which the palm is turned forward. 4. Circumduction It is a movement in which the distal end of a bone moves in a circle while the position of proximal end remains relatively stable.

33. Ⅳ ) The types of Synovial Joints They can be classified according to the number of bones, the axis and the type of movement or the shape of articular surface etc. They can be classified according to the number of bones, the axis and the type of movement or the shape of articular surface etc.

34. 1. The uniaxial joints They permit movement only in one axis (coronal, sagittal or vertical). 1) The hinge joints (or trochlear joints) They permit flexion and extension, e.g., the interphalangeal joints. 2) The pivot joints They allow rotation around a long axis, e.g., the proximal radioulnar joint permits rotation of the head of radius.

35. 2. The biaxial joints They allow movement in two axes which meet at right angle to each other. They allow movement in two axes which meet at right angle to each other. 1) The ellipsoid joints (or condyloid joints) They permit flexion and extension, adduction and abduction, as well as circumduction. Their articular surfaces are ellipsoidal or oval in shape, e.g., the radiocarpal joint. 1) The ellipsoid joints (or condyloid joints) They permit flexion and extension, adduction and abduction, as well as circumduction. Their articular surfaces are ellipsoidal or oval in shape, e.g., the radiocarpal joint. 2) The saddle joints 2) The saddle joints Their articular surfaces are concave and convex, opposite to each other. Their articular surfaces are concave and convex, opposite to each other. They allow movement of flexion, extention, adduction, abduction and circumduction. The carpometacarpal joint of the thumb is a good example. They allow movement of flexion, extention, adduction, abduction and circumduction. The carpometacarpal joint of the thumb is a good example.

36. 3. The multiaxial joints 1) The plane joints (or gliding joint) 1) The plane joints (or gliding joint) Some of these joints are referred to the multiaxial joints. But they permit only a little of movement, e.g., the acromioclavicular joint. Some of these joints are referred to the multiaxial joints. But they permit only a little of movement, e.g., the acromioclavicular joint. 2) The ball and socket joints 2) The ball and socket joints They are the most freely moving synovial joints. They are the most freely moving synovial joints. Universal movements are permitted (i.e., in an almost infinite number of axes), such as flexion and extension, adduction and abduction, medial and lateral rotation, and circumductiom, for example, the shoulder and hip joints. Universal movements are permitted (i.e., in an almost infinite number of axes), such as flexion and extension, adduction and abduction, medial and lateral rotation, and circumductiom, for example, the shoulder and hip joints.